Problem: Simplify the following expression: ${4z+9+8z+3}$
Rewrite the expression to group the ${z}$ terms and numeric terms: $ {4z + 8z} + {9 + 3}$ Combine the ${z}$ terms: $ {12z} + {9 + 3}$ Combine the numeric terms: $ {12z} + {12}$ The simplified expression is $12z+12$